Sulfuric acid reaction product of 2-mercapto-4, 6, 6-trimethyl thiazine



Patented Apr. 20, 1948 u m A01 an -Ion P K DIIQT or 2-MErtCaP'r-e.,6ATRIMETHYL THIAZINE Jacob Eden Jansen, Akron, Ohio, assignor to TheB. -F. 'IGoodrich .Company; 1 New york; .Y.', a corrorationnf New york nDrawing. Application July 31, 1946,

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. :1 This invention relates tonew vcompositionspf matter and pertainsmore particularlytothereaotion product of2-mercapto-4,6,6atrimethylthiazine with sulfuric acid of. aconcentration .ofc80% or greater, as well ,as .to the ,metal salts .of.the reaction product.

More particularly, the inventioncomprises subjecting-2-mercapto-4,6,6etrimethylthiazine t0 the action of concentratedsulfuric .acid, 80% t0 oleum, and maintaining .the temperature .of. thereaction mixture at that which the exothermic reaction has created(about 70 to 780 C. whenthe reactants are initiallyat room temperature)until the-evolution of sulfur dioxidehas ceased. ,The resulting productis isolatedby allowing the mass to-cool to about50 C., thenadding coldWater, to themixture with stirring, at which time the reaction productformsas afinely-divided solid, and recovering the...product .byfiltration.

- The alkalimetal salts of the reaction product, such as thesodiumandpotassium salts are water soluble and are preparedsimplyloy addingthereaction product to a concentrated alkali solution andthen removing the.water by evaporation. Qther metal; salts .aregenerally water. insolubleand are quite easily prepared byadding an aqueous-. s,o .uti,o n of asalt ,of the desired metal to an aqueous solution of. an al al met sa vo he reaction product. For example such ,metal salts of the reactionproductas the cadmium, zinc, lead, iron, manganese, magnesium, nickel,copper, calcium, barium, aluminum and mercury salts can be prepared inthis manner.

2-mercapto-4,6,6-trimethyl thiazine which is used in preparing thecompositions of this invention can be prepared by reactingdithiocarbamic acid with mesityl oxide, preferably by adding a salt ofdithiocarbamic acid to a mixture of mesityl oxide with an aqueoussolution of hydrochloric acid at a temperature of about 0 to 40 C. andthen heating the reaction mixture, as is more fully described in mycopending application Serial No. 557,384, filed October 5, 1944,particularly in Example I thereof.

The following specific examples of the preparation of the product of thereaction of Z-mercapto- 1,6,6-trimethylthiazine with concentratedsulfuric acid and the preparation of the metal salts of the reactionproduct are intended to be illustrative only.

Example I 250 parts by weight of 2-mercapto-4,6,6-trimethylthiazine and300 parts by weight of concentrated sulfuric acid (95.5% H2504) weremixed together in an acid resistant container. The bright red viscoussolution that formed 'was acco'rr' paniedby a good evolution of sulfurdioxide and a rise intemperature-from room temperature to about- 0; -Thr'eactionmixture Was stirred and heated at about 75 C. for about 30minutes when the evolution of sulfur dioxide had essentially ceased.T-he masswas' allowed to cool to about 50 o. 'and thfi "1000 partsi'byweight or 'cold water were added"with stirring. The finelyivisiedreflereeli Wes KQ PY IF b f ltr n newsstand d de .1ee t -br we t o h PfiPPWQWP WW reeeve e end W pPp nt -tt prqitotha j indefin te me tin eieintr net-91- 53 0 fiet mo er. h s .191 end hes h follow, he ons tioesnar not. cr iiw Pu merely th s =-teai are theh s e ult l 9 ub t l thesame product can be tained by varying the re eri n an committee re t tFor example, the preferred concentration of sul- Z9 a i @.%;r1 i ran hiL n Q%;1Qifind ole mbgnalsptieseohe -theP ep rat o the a un o r mmen edi .129 r ma is h anount h metered-t .p odu a urr 9i more: enqxw iqhe ldheasily handled tax-th .erdiee y meih d ;e ye i a eproduction. The abovesmrr tan also be prenarecier eddies il s reeei enii ii re t the WaterThis procedure is preferred for large-scale production, for it reduceslocalized heating brought about by the dilution of the acid where thewater first enters the reaction mixture.

Example II A slurry of 150 parts by weight of the reaction product ofExample I and 1,000 parts by weight of water was made up. To this slurrywas added 139 parts by weight of a caustic soda solution, 98% NaOH,which gave a clear, brown solution with which was mixed an aqueoussolution containing 289 parts by weight of lead nitrate and 1500 partsby weight of water. A heavy paste was formed which thinned out duringcontinued stirring, and the product was recovered by filtration, washedwith water and dried with warm air. There was obtained 164 parts byweight of the lead salt of the reaction product, a dry tan,finelydivided solid, which melted at a temperature range of -155" 0.

Example III The zinc salt of the reaction product of Example I was madeusing 118 parts by weight of tural and synthetic rubbers and as startingreaca tants for chemical synthesis. The sodium and potassium saltspossess the properties of good wetting agents.

To illustrate the use of these compounds as accelerators ofvulcanization, the following rubber for the preparation of the compoundsof my invention, I do not desire nor intend to limit myself solelythereto, for, as hitherto stated, the precise proportions of thematerials used may be varied and other materials having equivalentchemical properties may be employed, if desired, without departing fromthe spirit and scope of the invention as defined in the appended claims.

I claim:

1.A composition of matter selected from the class consistingof (1) thesulfuric acid reaction product of '2-mercapto-4,6,6-trimethylthiazine,said reaction product being formed by reacting2-mercapto-4,6,6-trimethylthiazine with concentrated sulfuric acid ofthe concentration of 80% to oleum at a temperature of from about C. to75 C., the reaction being characterized by the evolution of asubstantial amount of sulfur dicompositions in which the parts are byweight, were prepared and vulcanized at 280 F.

Parts Natural rubber 100 Carbon black -50 Stearic acid 3.5 Pine tar 3.0Zinc oxide p 5.0 Antioxidant 1.0 Sulfur V 3.0 Mercaptobenzothiazole(sample A) 1.0

, p 7 Parts Product of Example I (sample B) 1. 75 Product of Example 11(sample C) 1.5 Product of Example 111 (sample D) 1.5

Sample A was prepared as a, basis for comparing the activity of thesenew compounds as vulcanization accelerators. Sample A reached itsmaximum tensile strength of 4200 pounds per square inch after 75 minutesof vulcanization while sample B attained an ultimate tensile strength of4200 pounds per square inch after only 45 minutes of vulcanization.Samples C and D reached an ultimate tensile strength of 3780 and 3400pounds per square inch respectively after 75 minutes of vulcanization. I

These new compositions are equally as efiective for the vulcanization ofsulfur vulcanizable synthetic rubbers such as'the copolymers ofbutadiene-1,3 and styrene. and 'the' copolymers of butadiene-1,3 andacrylonitrile. They are also effective with other sulfur vulcanizablerubbers such as reclaimed natural rubber, balata, gutta percha and thelike. I

While I have herein described specific methods oxide, heating thereaction mixture until evolution of sulfur dioxide has ceased, andseparating the resulting reaction product, and (2) the metal salts ofsaid reaction product.

2. The sulfuric acid reaction product of 2-mercapto-4,6,6trimethylthiazine prepared by reacting2-mercapto-4,6,6-trimethylthiazine with sulfuric acid of theconcentration of 80% to oleum at a temperature of from about 20 C. toC.. the reaction being characterized by the evolution of a substantialamount of sulfur dioxide, heatingthe reaction mixture until evolution ofsulfur dioxide has ceased, and separatingthe resulting reaction product.

3. The zinc salt of the sulfuric acid reaction product of2-mercapto-4,6,6-trimethylthiazine, said reaction product being definedin claim 2.

4. The lead salt of the sulfuric acid reaction product of2-mercapto-4,6,6-trimethylthiazine, said reaction product being definedin claim 2.

5. The method of preparing the sulfuric acid reaction product of claim 2which comprises subjecting 2-mercapto-4,6,6-trimethylthiazine to theaction of sulfuric acid of the concentration of about to about that ofoleum at a temperature'of about 20 C. to 75 C., said reaction beingcharacterized by the evolution of substantial quantities of sulfurdioxide, heating the reaction mixture until the evolution of sulfurdioxide has ceased, and separating the resulting reaction product.

' JACOB EDEN JANSEN.

